During the 2018 season the Shenandoah Audubon/Blandy Bluebird Trail participated in Sparrow Swap, a citizen science project conducted by the North Carolina Museum of Natural Sciences located in Raleigh, North Carolina. House sparrows (Passer domesticus) are an invasive bird species to North America and are not protected by the Migratory Bird Treaty Act. They are known to wreak havoc for our cavity-nesting birds by taking nesting habitat, breaking eggs, killing chicks and even adult birds.
One lone female house sparrow was first detected in a single nestbox on the trail in 2009. The monitoring team immediately implemented an egg removal protocol to prevent the sparrow from reproducing and 8 viable eggs were removed and discarded. As the viable eggs were removed, we replaced them with unmarked wooden eggs purchased from a craft house. No house sparrows or nests were reported again on the trail until 2014; that year, they occupied 3 boxes and laid 17 eggs, all of which were discarded. To demonstrate how quickly house sparrows can multiple even when efforts are made to keep them in check, this past season they occupied 9 boxes and laid 45 eggs!
Before the 2018 season started I had read about Sparrow Swap. It would be a lot of work but I decided that instead of discarding the eggs, we would put them to good use and joined Sparrow Swap. As our team detected viable house sparrow eggs throughout the season, we carefully removed and placed them in plastic containers of bird seed to prevent breakage and stored them in the refrigerator until time of shipping. This time we replaced the viable eggs with fake wooden eggs provided by the researchers which were painted with speckling to look just like real house sparrow eggs!
Monitoring, collecting, replacing, labeling, storing, preparing for shipping and reporting took many hours. However, our team is contributing to the Sparrow Swap project objectives by making it possible to study the following: photographing and analyzing the variation in color and speckling of the eggs to look at the geographic patterns in eggs, studying best methods for controlling avian pests, and eventually the eggs will be analyzed for contaminants as part of research to determine whether house sparrow eggs are a useful indicator of human exposure to environmental contaminants.
By Kaycee Lichliter